factor is buggy :

factor 100000000000000000000000000000000000000

100000000000000000000000000000000000000: 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5

http://www.wolframalpha.com/input/?i=factor+1000000000000000...

also numfmt bug:

$ numfmt --to=iec 999999999999999999939999999 828Y

$ numfmt --to=iec 999999999999999999940000000 numfmt: value too large to be printed: '1e+27' (cannot handle values > 999Y)

but 999999999999999999939999999 is ~1000YB : http://www.wolframalpha.com/input/?dataset=&i=99999999999999...